1. Field of the Invention
This invention relates to a novel compound useful as a herbicide for agriculture and horticulture, to a herbicidal composition containing the compound, and to a process for preparing the compound.
2. Description of the Prior Arts
It has been developed to control annual weeds such as barnyard grass (Echinochloa crus-galli BEAUV) and toothcup (Rotala indica KOEHNE) by a treatment of a herbicide at the initial stage of growth of rice plants. However, it has not been enough to control perennial weeds such as bulrush (Scirpus Juncoides var. Hotarui), chufa (Cyperus microiria STEUD), water plantain (Sagittaria trifolia L) and arrowhead (Sagittaria pygmaea MIQ), whereby such perennial weeds have grown thick to prevent the growth of rice plants. Thus, the control of these perennial weeds has been required. It has been proposed to use 4-benzoyl-5-hydroxypyrazole derivatives as herbicides being active against these perennial weeds in U.S. Pat. No. 4,063,925.
The inventors have studied on novel compounds of 4-benzoyl-5-hydroxypyrazole derivatives having hydrocarbon moiety bonded by an ether bond at 5-position of the pyrazole ring and have found that the specific novel compounds impart excellent herbicidal effect to these perennial weeds without any phytotoxicity to rice plants and impart superior herbicidal effect to the annual weeds at the initial stage of growth to the known 4-benzoyl-5-hydroxypyrazole derivatives.